Within the proposed Center for Advancing Longitudinal Drug Abuse Research (CALDAR), the structure and functions of the Coordination &Integration (C&I) Core are focused on the coordination, promotion, and implementation of longitudinal studies with careful monitoring and quality control as well as internal and external evaluation of Center activities. CALDAR will perform these functions through a system of committees and advisors under the guidance of the C&I Core, where Core activities are designed to promote frequent, productive interactions among investigators. The unifying theme of the Center research is the development and application of rigorous scientific approaches for advancing longitudinal research on drug abuse and its interplay with drug treatment and other service systems. CALDAR activities conducted in the context of this theme will provide empirical information to support the development of improved clinical practice and policy decisions within and across service systems. To serve the Center's overall theme and goals, the C&I Core has the following specific aims: (1) to provide administrative support and scientific leadership across Center Cores and projects to improve the scientific quality and facilitate the productivity of longitudinal research on drug abuse and its interplay with drug treatment and other service systems;(2) to provide a mechanism for scientific interaction, collaborative research, and cross-project analyses to improve the science of longitudinal research on drug abuse and its interplay with service systems;(3) to coordinate education of researchers, clinicians, and policymakers on longitudinal research methods and on utilization of findings based on longitudinal research;and (4) to coordinate and promote dissemination of findings of longitudinal research on drug abuse and its interplay with service systems. C&I Core functions are crucial to maintaining a highly integrated Center, to facilitating research rigor, quality, and productivity, and to disseminating research findings.